Page 119 - Mirjam-Theelen-Degradation-of-CIGS-solar-cells

Temperature dependency of the electrical parameters of CIGS solar cells

-0.3
o C) -0.4 o C) -0.3 SLG Au
Temperature coefficient (rel %/ -0.5 SLG Au Temperature coefficient (rel %/ -0.4
PI
SLG In

-0.6
-0.7
SLG In
10 15 PI -0.5 500 550 600 650
Efficiency(%) SLG Au 0.0 Open circuit voltage (mV)
Temperature coefficient (rel %/ o C) 0.1 SLG In Temperature coefficient (%/ o C) -0.1 SLG Au
PI

0.0
-0.2
SLG In
-0.1 -0.3 PI
20 25 30 35 40 40 50 60 70 80
2
Short circuit current density (mA/cm ) Fill factor (%)
Figure 4.5
Normalised temperature coefficients of the efficiency, open circuit voltage, short circuit current density and fill factor as a
function of these parameters at room temperature.

large number of factors.
Additionally, Figure 4.5 shows the normalised temperature coefficients of the
efficiency, V , J and fill factor as a function of their values at room temperature.
sc
oc

4.4 Discussion
In this chapter, an overview about the physical explanations of the temperature
dependency is given. For more in-depth information, the reader is referred to
reference [19].

Reference [6] has reported that it is commonly expected that a temperature rise leads
to an open circuit voltage and fill factor drop and a slight increase in the short circuit
current. As a result, this leads to a reduction in the efficiency. The decrease of open
circuit voltage, as well as fill factor and efficiency was observed, while the short circuit
current showed a less expected picture. In Tables 4.2 and 4.3 and Figure 4.3, the most
surprising observation is the behaviour of the short circuit current density. The CIGS
on PI has a positive temperature dependency for the short circuit current density,

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